PLEA Network

30 August 2023, NOAA: Does it matter how much the United States reduces its carbon dioxide emissions if China doesn’t do the same? Yes, it matters. Observed and anticipated increases in greenhouse gas emissions from China and other countries don’t let Americans off the hook for reducing emissions. From a purely physical perspective, any reduction in emissions helps minimize future temperature increases. From the perspective of fairness, the United States has released more heat-trapping gases to date than either China or India, the world’s two most populous countries. Carbon dioxide is a long-lived greenhouse gas that can linger in Earth’s atmosphere for thousands of years. Consequently, the United States bears more responsibility for the amount of warming that has occurred so far and will persist for millennia. The global carbon budget. The United States, along with close to 200 other countries, is a party to the 2015 Paris Agreement. The agreement aims to limit “the increase in the global average temperature to well below 2°C [3.6 ˚F] above pre-industrial levels.” Participating nations also agree to try “to limit the temperature increase to 1.5°C [2.7 ˚F] above pre-industrial levels.” To meet these goals, humans can emit only so much more carbon dioxide, whether through fossil fuel burning, cement production, or land use change. Just as a household working with limited financial resources must adhere to a financial budget, nations trying to limit further warming must collectively adhere to a carbon budget… Unfortunately, most of the estimated global carbon budget for the 1.5°C target has been spent. The AR6 concluded that humans had already burned through about four-fifths of the budget. In November 2022, the Global Carbon Project published updated estimates of the allowable carbon emissions to limit further warming. Taking into account the continued emissions since the IPCC AR6 publication, the Global Carbon Project estimated that maintaining a 50 percent chance of meeting the 1.5°C target meant limiting future emissions to 380 billion metric tons. Maintaining a 50 percent chance of meeting the 2°C target meant limiting future emissions to 1,230 billion metric tons. Read more here